Multiple-phase ejector refrigeration system



Oct- 11, c KEMPER ETAL MULTIPLE-PHASE EJECTOR REFRIGERATION SYSTEMOriginal Filed Sept. 13. 1963 2 Sheets-Sheet 1 I03 IIO'\ 20 lOZ HEATEXCHANGER 1 I v EVAPORATOR 2/ 26 3o 25 I3 p r' J FIGURE I 33 35 VAPORCOMPRESSOR FIS EVAPORATOR BOT 25 I2 HEATER 2| l9 J FIGURE 2 34 INVENTORSCLARENCE A. KEMPER GEORGE E HARPER GEORGE A. BROWN BYZ w ATTORNEYS Oct.11, 1966 c. A. KEMPER ETAL 3,277,660

MULTIPLE-PHASE EJECTOR REFRIGERATION SYSTEM Original Filed Sept. 13,1963 2 Sheets-Sheet 2 lOl H2 107 I03 0 H4 HI i I08 I I09 H3 7 k IOZLIQUID-VAPOR 1 I SEPARATOR 32 VAPOR I COMPRESSOR |6 f 33 3| OMPRESSEDVAPOR 26 I2 HEAT 22 i8 EXCHANGER f 24 28 EVAPORATOR HEATER l3 FIGURE 3INVENTORS CLARENCE A-KEMPER GEORGE E HARPER GEORGE A-BROWN BY ATTORNEYSUnited States Patent 3,277,660 MULTIPLE-PHASE EJECTOR REFRIGERATIONSYSTEM Clarence A. Kemper, Lexington, George F. Harper, Wayland, andGeorge A. Brown, Lexington, Mass., assignors to Joseph Kaye & Co., Inc.,Cambridge, Mass., a corporation of Massachusetts Continuation ofapplications Ser. No. 308,907, Sept. 13,

1963, and Ser. No. 489,107, Sept. 22, 1965. ThlS application Dec. 13,1965, Ser. No. 513,210 33 Claims. (Cl. 62116) This is a continuation ofof applications, Serial Numbers 308,907, filed September 13, 1963, and489,107, filed September 22, 1965, both of which are now abandoned.

The present invention relates to improved apparatus for and methods ofcompression of refrigerant and other vapors, being more particularlyrelated to an improved refrigeration system employing novelmultiple-phase ejector apparatus.

Refrigeration systems commonly require a vapor compressor in order tocondense the vapor from the evaporator at a higher temperature than thatof the object or environment being cooled. Vapor compressors aregenerally characterized by being relatively high in cost, size and inoperating noise level. We have now discovered an improved refrigerationapparatus and method that permits the replacement in whole'or part ofthe vapor compressor of conventional refrigeration systems by theemployment of a novel multiple-phase ejector system having advantages ofsimplicity, small size, reliability, and a minimum number of movingparts.

In such vapor compressing systems, vapor which is generated by theevaporation of liquid at some desired temperature and pressure iscompressed to higher pressure so that the heat introduced to the systemat the temperature of the evaporation process may be rejected from thesystem at a higher temperature. The vapor in such systems is generallycompressed by employing the above-mentioned mechanical vaporcompressors, or vapor-driven ejectors, or liquid-driven ejectors. Ournoval multiplephase ejector for compressing vapor, however, does notsuffer from the operational limitations of such prior me chanical vaporcompressor, and, in addition, is more efficient than vapor-driven andliquid-driven ejectors.

An ejector (sometimes called an injector, jet pump or jet compressor) isa device in which two fluid streams flow in intimate contact atrelatively high velocity such that the driving stream transfers momentumto the driven stream, thereby increasing the stagnation pressure of thedriven stream. The two fluid streams are accelerated in separate nozzlesto approximately the same pressure before being brought together in amixing section, and the mixed stream is decelerated in a diffuser. Theprincipal sources of inefliciency in such ejectors are momentum transferthrough large velocity differences and heat transfer through largetemperature differences which exist between the driving and drivenstreams. In vapor compression systems, such as refrigeration systems andthe like, the driven stream is vapor or a high-quality two-phase mixtureat a relatively low temperature. If such driving stream is vapor or ahigh-quality two-phase mixture having approximately the same specificvolume as the driven stream when the two streams enter the mixingsection, there must be a large velocity difference between the twostreams in order for the driving stream to transfer suf- "ice ficientmomentum to the driven stream. If the driving stream is liquid, obtainedfrom the condensation process of the cycle, there will be a largetemperature difference between the driving stream and the driven streamproviding for inefficient heat transfer between the two streams.

The multiple-phase ejector, however, utilizes low-quality, two-phase,liquid-vapor fluid as the driving stream. Before entering its nozzle andbeing accelerated, the driv ing stream may be compressed liquid,saturated liquid, or a low-quality, two-phase, liquid-vapor fluid. Whenthe driving stream is a two-phase fluid at stagnation conditions, thedriving stream nozzle may be either a simple convergent nozzle or it maybe a convergent-divergent nozzle depending on the operating conditionsof the cycle. When the driving stream is liquid at stagnationcondiditions, however, the driving stream nozzle must, in accordancewith our findings, be a convergent-divergent nozzle in order for thedriving stream to be accelerated efficiently, and the driving streambecomes what We term a supersonic velocity stream, in that the square ofthe local average velocity is greater than the differential change ofpressure with density in an isentropic expansion.

Hereinafter, the term liquid stream or liquid refrigerant stream will beemployed to refer to a fluid stream which may be pure liquid or may be alow-quality, two-phase, liquid-vapor fluid being mostly liquid by mass;and the term vapor stream or vapor refrigerant stream will be employedto refer to a fluid stream which may be pure vapor or may be ahigh-quality, two-phase, liquid-vapor fluid, mostly vapor by mass.

When a multiple-phase ejector is employed as a vapor compressor in avapor compression system, such as a refrigeration system, the drivingstream is obtained from the ejector exit-stream by some process. Thedriving stream must have a higher stagnation pressure and a higherdensity than the ejector exit-stream. Since the ejector exit-stream is,in general, a two-phase, liquidvapor fluid, there are several processesby which a higherpressure, higher-density stream may be obtained. Theejector-exit stream may be condensed to form a pure liquid stream, partor all of which is pumped to a higher pressure by a liquid pump; theejector-exit stream may be separated to form a liquid stream and a vaporstream with part or all of the liquid stream being pumped to a higherpressure by a liquid pump; or the ejector-exit stream may be separatedto form a liquid stream and a vapor stream with part or all of the vaporstream being compressed to a higher pressure in a vapor compressor andsubsequently being condensed to form a liquid stream. All of theprocesses above involve adding energy to the system in the form of workand yield a liquid stream which is at a stagnation pressure greater thanthat of the ejector exit-stream. In some applications, it may bedesirable to add additional energy to the system in the form of heat byincreasing the temperature of the liquid stream to a value higher thanthat of the ejector exitstream, and, if desired, partially to evaporatethe stream at the higher temperature to form a low-quality, twophasedriving stream. In the latter case, the quality of the partiallyevaporated stream should be such that it contains no more thansubstantially fifty percent vapor by mass.

In an ejector, the driving and driven streams enter the mixing sectionat approximately the same pressure. -In a multiple-phase ejector, thedriving stream enters the mixing section as a low-quality, two-phasefluid, and the driven stream enters the mixing section as saturatedvapor or as a high-quality two-phase fluid. When the same substance isemployed in the two streams, therefore, they will enter the mixingsection at approximately the same temperature, and any heat-transferbetween the streams or between the liquid and vapor phases of any onestream will occur through small temperature differences, such processbeing thermodynamically more eflicient than heat-transfer through largetemperature differences. Since the driving stream has a greater densitythan the ejector exit-stream, it will have a greater density, or lowerspecific volume, than the driven stream. The enthalpy change for adifferential pressure change during an isentropic expansion isproportional to the specific volume of the fluid, and the velocity of astream starting from rest and undergoing an isentropic expansion isproportional to the square-root of the enthalpy change experienced bythe stream. Where the driving stream is accelerated from a highstagnation pressure and has a lower specific volume than the drivenstream, it has been found possible to design a multiple-phase ejectorsuch that the driving and driven streams enter themixing section atapproximately the same values of velocity. The momentum transfer betweenthe streams or between the liquid and vapor phases of any one streamwill thus occur through small velocity diEerences--a process moreefficient than momentum transfer through large velocity diiferences.

An object of the present invention, accordingly, is to provide a new andimproved multiple-phase ejector system which is more efiicient thanordinary ejectors, because the inefliciencies due to heat-transfer andmomentum-transfer are minimized.

Since the multiple-phase ejector is more efiicient than ordinaryejectors, refrigeration systems employing such a multiple-phase ejectoras the vapor compressor will be more eflicient than refrigerationsystems employing ordinary ejectors.

A further object of our invention, accordingly, is to provide a new andimproved apparatus for and method of compression of refrigerant andother vapors.

Another object of our invention is to provide improved refrigerationsystems and methods embodying the vapor compression apparatus and methodabovementioned.

Other and further objects will be hereinafter explained and more fullydelineated in the appended claims.

The invention will now be described in connection with the accompanyingdrawing, FIG. 1 of which is a combined partial cross-sectional view of amultiple-phase ejector and a block diagram of a preferred embodiment ofa multiple-phase ejector refrigeration system;

FIG. 2 is a modification of portions of the system of FIG. 1, and

FIG. 3 is a combined cross-sectional view of a multiplephase ejector anda block diagram of another embodiment of a multiple-phase ejectorrefrigeration system.

Referring to FIG. 1, a multiple-phase ejector of a preferred type isillustrated at 100, having an input inlet 103 for the introduction of ahigh-pressure liquid stream communicating with a first nozzle 104discharging into a mixing chamber 112 having its flow axis substantiallyaligned with the longitudinal axis of the nozzle 104. The nozzle 104 iscontoured by respective converging-diverging internal flow paths 105 and109 in which the minimum cross-sectional area at 113 is sufficientlysmall relative to the outlet area and other dimensions at 108 as toenable the production of a supersonic, high-velocity, two-phase,liquid-vapor stream, as described previously. A second input inlet 102is provided for the introduction of a lowpressure vapor streamcommunicating through a chamber 106 with a second nozzle 107 locatedsubstantially con- 4 p centric with the first nozzle 104 for introducingat 111 a high-velocity vapor refrigerant stream into the inlet openingof the mixing chamber 112 so as to be placed in intimate contact withthe two-phase stream resulting at 108 from the first nozzle 104, therebyto combine the streams. The resulting mixed stream continues through themixing section and a section 114 of substantially constant flow areainto a diverging chamber 116, the function of the latter of which is todecrease the velocity of the combined streams at 110 to a velocity atwhich the temperature and the pressure of the combined stream is greaterthan the temperature and the pressure of'the vapor refrigerant streamprior to passage through the second nozzle 107. The divergent chamber116 has an outlet at 101 from which the ejector-exit stream iswithdrawn. The ejector-exit stream is at a higher pressure and a highertemperature than the vapor stream which was introduced at 102.

When the liquid stream introduced at 103 is substantially pure liquid,the nozzle 104 must be a converg-.

cut-divergent nozzle as shown. When the liquid stream introduced at 103is a two-phase, liquid-vapor stream, the. nozzle 104 may be aconvergent-divergent nozzle or may be a simple convergent nozzle. Thenozzle 104 may be and preferably is a single nozzle as shown, or, ifdesired, ;a plurality of nozzles may be employed on one or moremultiple-phase ejector inlet conduits; or a plurality of nozzles may beplaced in any arrangement which permits the rapid and efficientintroduction of a liquid stream and a vapor stream from conduits 103 and102, respectively, into the inlet opening of the mixing chamber 112. Inthe embodiment shown in FIG. 1, the liquid stream is introduced throughthe central nozzle 104 and the vapor stream is introduced through theconcentric annular nozzle 107. The operation may also be effected by theintroduction of the vapor stream through a central nozzle and theintroduction of the liquid stream through a concentric annular nozzle.-In the embodiment shown, the multiple-phase ejector has-a mixing chamber112 with an'inwardly sloping contour connected to the short section 114of constant flow area. Mixing sections having geometries different fromthat shown may also be employed for use in the multiple-phase ejector.

The ejector-exit stream withdrawn at 101 may be and preferably is atwosphase, liquid-vapor fluid or, if desired, may be a completelycondensed liquid stream con-. taining only trace amounts ofnon-condensible gases. The latter condition will find particular utilityin rejection of heat from space vehicles where the absence of agravitational field implies the need of a condensation process otherthan the conventional one which depends on the existence of agravitational field for removal of the con-' densate from the condensersurfaces.

Referring again toFIG. l, a multiple-phase ejector.

refrigeration system is illustrated having, in one mode of operation,the multiple-phase ejector 100 of the type described above to which isintroduced the high-pressure liquid stream at 103 and the low-pressurevapor stream at 102, and from which is withdrawn a single two-phase,liquid-vapor refrigerant stream at 101 having ahighen pressure and ahigher temperature than the vapor stream at 102. The single streamwithdrawn at 101 is applied through conduit 20 to a heat exchanger 22 inwhich 'the'j vapor portion of the stream is condensed," thereby re-.jecting heat from the system. The liquid stream withdrawn from the heatexchanger 22 through conduit 24' is divided into two portions; the firstportion of which is applied through a conduit 26 to a'Jouleinson valve Vor similar structure 28, whereby the stream is 'expanded to a lowerpressure and is applied through conduit 30 to; anevaporator 18. Theliquid is thus evaporated and, in so doing, absorbs heat from theenvironment-to-be-cooled.I The vapor withdrawn from the evaporator 18through conduit 25 maybe applied either'directlyto' the'vapor inlet 102of the multiple-phase ejector 100 through conduits 16 and 35, as in FIG.1, or along an alternative path through conduit 32 to a vapor compressor31, FIG. 2, whereby its pressure is increased, and thence throughconduits 33 and 35 to the vapor inlet 102 of the multiplephase ejector100.

The second portion of the liquid stream at 24, in FIG. 1, is appliedthrough conduit 13 to a pump 14 which increases its pressure. The highpressure liquid at 15 is applied either directly to the liquid inlet 103of the multiple-phase ejector 100 through conduits 17 and 12, as in FIG.1, or along an alternative path through conduit 19, FIG. 2, to a heater34 and thence through conduits 21 and 12 to the liquid inlet 103 of themultiple-phase ejector 100. When the heater 34 is employed, as in themodification of FIG. 2, the pump 14 serves the purpose of increasing thepressure of the liquid from the heat exchangeer 22 so that the liquidmay be heated at 34 to a higher temperature, thereby accepting heatenergy without evaporation. Once at such higher temperature, if desired,the fluid at 34 may be partially evaporated before introduction to theliquid inlet 103 of the multiple-phase ejector 100.

Thus, in one embodiment, the total energy-input to operate the system isintroduced in the form of work by pump 14, in which case the vapor at 25is applied directly through conduits 16 and 35 to the vapor inlet 102 ofthe multiple-phase ejector 100, and the high pressure liquid at 15 isapplied directly through conduits 17 and 12 to the liquid inlet 103 ofthe multiple-phase ejector 100.

In the embodiment of FIG. 2, however, the energyinput to operate thesystem may be shared between the pump 14 and the heater 34, in whichcase the vapor at 25 is applied directly through conduits 16 and 35 tothe vapor inlet 102 of the multiple-phase ejector 100 and the liquid at15 is applied through conduit 19 to the heater 34, whereby thetemperature of the stream is increased, adding energy to the system inthe form of heat, and thence through conduits 21 and 12 to the liquidinlet 103 of the multiple-phase ejector. In this mode of operation, theliquid stream introduced at 103 may be pure liquid or may be alow-quality, two-phase, liquid-vapor fluid containing no more than aboutfifty percent vapor by mass and having a pressure greater than thedesired pressure at the exit 101 of the multiple-phase ejector 100.

In still another embodiment, the energy-input to operate the system maybe shared between the pump 14 and a vapor compressor 31, FIG. 2, inwhich case the high pressure liquid at 15 is applied directly to theliquid inlet 103 of the multiple-phase ejector 100 through conduits 17and 12 and the vapor at 25 is applied through conduit 32 to the vaporcompressor 31 in which the pressure of the vapor is increased, therebyadding work to the system. The vapor leaving the vapor compressor 31 isapplied to the vapor inlet 102 of the multiple-phase ejector 100 throughconduits 33 and 35. In this mode of operation the pressure at the exit101 of the multiple-phase ejector is greater than the pressure of thevapor at 102 and less than the pressure of the liquid at 103.

In still another embodiment, the energy-input to operate the system maybe shared among the pump 14, the heater 34 and the vapor compressor 31,in which case the vapor at 25 is applied through conduit 32 to the vaporcompressor 31 in which the pressure of the vapor is increased (therebyadding work to the system), and thence through conduits 33 and 35 to thevapor inlet 102 of the multiplephase ejector 100. The liquid at 15 isapplied through conduit 19 to the heater 34, whereby the temperature ofthe stream is increased (adding energy to the system in the form ofheat), and thence through conduits 21 and 12 to the liquid inlet 103 ofthe multiple-phase ejector. As in the embodiments described above, inthis mode of op eration the pressure at the exit 101 of themultiple-phase ejector 100 is greater than the pressure of the vaporstream at 102 and less than the pressure of the liquid stream at 103,and the liquid stream at 103 may contain no more than substantiallyfifty percent vapor by mass.

Referring to FIG. 3, a multiple-phase ejector refrigeration system isillustrated having a multiple-phase ejector of the same type describedpreviously. The twophase, liquid-vapor stream at the exit 101 of themultiplephase ejector 100 is withdrawn through conduit 20 and applied toa liquid-vapor separator 30 whereby the stream is separated into aliquid portion and a vapor portion. The liquid portion is withdrawn fromthe liquid-vapor separator 30 through conduit 26 and is applied to theJoule- Thomson valve or similar structure 28, whereby the stream isexpanded to a lower pressure and is applied through conduit 30 to anevaporator 18, thereby evaporating the liquid and in so doing absorbingheat from the environment-to-be-cooled. The vapor withdrawn from theevaporator 18 through conduits 16 and 35 is applied directly to thevapor inlet 102 of the multiple-phase ejector 100.

The vapor portion is withdrawn from the liquid-vapor separator 30through conduit 32' and is applied to a vapor compressor 31, whereby thepressure of the vapor stream in increased, adding energy to the systemin form of work. The resulting high-pressure vapor is applied throughconduit 33 to heat exchanger 22, in order to desuperheat and condensethe vapor and to produce highpressure liquid at 24.

V The high-pressure liquid at 24 may be applied either to a path whichintroduces this liquid directly to the liquid inlet 103 of themultiple-phase ejector 100 through conduits 23 and 12, or it may beapplied along an alternative path through conduit 13 to the pump 14which further increases the pressure of the liquid.

The high-pressure liquid at 15 may be applied directly to the liquidinlet 103 of the multiple-phase ejector 100 through conduits 17 and 12or it may be applied along an alternative path through conduit 19 to aheater 34, whereby the temperature of the stream is increased, addingenergy to the system in the form of heat, and hence through conduits 21and 12 to the liquid inlet 103 of the multiple-phase ejector.

In one mode of operation of the system shown in FIG. 3, the totalenergy-input to operate the system is introduced by vapor compressor 31in the form of work as is typically done in conventionalvapor-compression refrigeration systems. In this embodiment, however, anadvantageous bootstrap type of operation takes place in accordance withwhich a saturated liquid stream is expanded to a lower pressure andtemperature in order to absorb heat from an environment and in which thevapor so produced is introduced to the vapor compressor at a pressurehigher than the saturation pressure corresponding to the temperature atwhich the heat was absorbed. Specifically, in the embodiment whereby thefluid applied to the liquid inlet 103 of the multiple-phase ejector 100is previously passed through conduit 23, the saturated liquid leavingthe heat exchanger 22 enters the nozzle 104 of the multiple-phaseejector in which its velocity is increased, thereby producing atwo-phase, supersonic, liquid-vapor stream at 108. The vapor produced inthe evaporator 18 enters the second nozzle 107 in which its velocity isincreased, and the two streams are brought into intimate contact in themixing chamber 112. The velocity of the combined stream is decreased insection 116 to provide a two-phase stream at the ejector exit 110 whichhas a higher pressure than the vapor which left the evaporator throughconduit 16 and entered the ejector at 102. This two-phase stream thenenters the liquidvapor separated 30 from which the liquid is drawn offthrough conduit 26 and from which the vapor is drawn off and introducedto the vapor compressor 31, whereby it is compressed to a higherpressure and temperature and returned by conduit 33' to the heatexchanger 22. The vapor introduced to. the vapor compressor 31 is at ahigher pressure than the vapor produced in the evaporator 18. The liquidwhich was withdrawn through conduit 26 enters the Joule-Thomson valve 28and is expanded to a lower pressure and temperature at 30 and enters theevaporator 18 in which it absorbs heat from the environment byevaporation to vapor at 16. In the typical refrigeration system, theliquid leaving the heat exchanger 22 would be passed immediately throughthe Joule- Thomson valve 28 into the evaporator 18 and the vaporgenerated in this evaporator and withdrawn through conduit 16 would beimmediately introduced to a vapor compressor whereby it would becompressed to a higher pressure and temperature and re-introduced toheat exchanger 22. The pressure of the vapor at 16 is lower than thatpressure generated by the multiple-phase ejector at 110.

Therefore, the vapor compressor 31, in this embodiment using themultiple-phase ejector, receives vapor at a higher pressure than doesthe vapor compressor of a typical refrigeration system operating withthe same temperature in the evaporator 18. Less work, therefore, isrequired .to compress this vapor to the same pressure in the heatexchanger at 22.

In one embodiment illustrated in FIG. 3, the energyinput to operate thesystem may be supplemented by additional work-input through the pump 14,in which case the high-pressure liquid at 24 is applied to the pump 14through conduit 13 and thence to the liquid inlet 103 of themultiple-phase ejector 100 through conduits 15, 17 and 12.

In a further mode of operation of the system of FIG. 3, moreover, theenergy-input to operate the system may be further supplemented by theaddition of energy in the form of heat, in which case the high-pressureliquid leaving the pump 14 through conduit 15 is applied through conduit19 to heater 34 and thence to the liquid inlet 103 cf the multiple-phaseejector 100 through conduits 21 and 12.

The refrigerant fluid employed in the refrigeration systems describedabove may be any low boiling point, high heat capacity, condensablerefrigerant fluid such as carbon dioxide, sulfur dioxide, water,ammonia, hydrocarbons, or'halohydrocarbons like mono and polychloro andfluoro substituted low molecular weight alkanes such as dichlorodifluoromethanes and trichloromonofiuoromethane and the like.

The refrigeration systems described above employ a single stagemultiple-phase ejector, but these systems, as before noted, may, ifdesired, employ more than one multiple-phase ejector arranged in seriesor in parallel in order to compress the refrigerant vapor obtained fromthe evaporator 18.

Further modifications will also occur to those skilled in the art andall such are considered to fall within the spirit and scope of theinvention as defined in the appended claims.

What is claimed is:

1. An improved refrigerant process which comprises:

providing a high pressure liquid refrigerant stream at inlet means;

providing a low pressure vapor refrigerant stream at said inlet means;

increasing the velocity of the low pressure vapor refrigerant stream;

- increasing the velocity of the high pressure liquid re- ,frigerantstream and forming a supersonic velocity two-phase vapor-liquidrefrigerant stream;

- mixing the two-phase vapor-liquid refrigerant stream with theincreased velocity v-apor refrigerant stream to provide a singlerefrigerant stream;

decreasing the velocity of the said single refrigerant stream to avelocity at which the temperature and pressure of the same are greaterthan the temperature and pressure of the vapor refrigerant stream beforeits increase in velocity; 4 increasing the pressure of a portion of thesaid single refrigerant stream to provide the said high pressure liquidrefrigerant; directing the high pressure liquid stream to said inletmeans; expanding the remaining portion of the said single refrigerantstream to a lower temperature and pressure; and placing the expandedportion in a heat absorbent relationship with a heat source to providesaid vapor refrigerant stream to said inlet means.

2. A process as claimed in claim 1 and in. which the said singlerefrigerant stream is condensed and the condensate divided into the saidportion that is increased in pressure and the said remaining portionthat is expanded.

3. A process as claimed in claim 1 and in which the said singlerefrigerant stream is separated into substantially liquid and vaporstreams the latter of which comprises the portion that is increased inpressure and the former of which comprises the said remaining portionthat is expanded.

4. A refrigeration system comprising, in combination:

inlet means for receiving a high pressure refrigerant liquid stream anda 'low pressure vapor refrigerant stream;

means for increasing the velocities of the streams including means forforming from the said liquid stream a supersonic velocity two-phasevapor-liquid refrigerant stream;

means for mixing the two-phase vapor-liquid refrigerant stream with theincreased velocity vapor refrigerant stream to provide a singlerefrigerant stream;

means for decreasing the velocity of the said single refrigerant streamto a velocity at which the temperature and pressure of the same aregreater than that of the vapor refrigerant stream at the said inletmeans;

means for increasing the pressure of a portion of the said singlerefrigerant stream to provide the said high pressure refrigerant liquidand for directing the same to said inlet means;

means for expanding the remaining portion of the said single refrigerantstream to a lower temperature and pressure; and

means for placing the expanded portion in a heat: absorbent relationshipwith a heat source to provide the said vapor refrigerant stream to saidinlet means.

5. A system as claimed in claim 4 and in which the said single stream isfed to heat exchanger means, the said pressure-increasing meanscomprises pump means connected to the heat exchanger means and the saidexpanding means comprises pressure expansion means connected with theheat exchanger means and connected through evaporator means with saidinlet means.

6. A system as claimed in claim 5 and in which supplemental heater meansis connected between the pump means and the said inlet means.

7. A system as claimed in claim 5 and in which vapor compressor meansis. connected between said evaporator means and said inlet means.

8. A system as claimed in claim 4 and in which the said single stream isfed to liquid-vapor separator means the resulting vapor portion of whichis fed to the said pressure-increasing means and the liquid portion ofwhich is connected with the said expanding means.

9. A system as claimed in claim 8 and in which the pressure-increasingmeans comprises vapor compressor means-connected with heat exchangermeans to the said inlet means.

10. A system as claimed in claim 9 and in which pump means is connectedwith or without supplemental heater means between the 'heat exchangermeans and the said inlet means.

11. A system as claimed in claim 8 and in which the said expanding meanscomprises pressure expansion 9 means connected through evaporator meansto said inlet means.

12. A vapor compressing apparatus which comprises,

in combination:

means for introducing a high-pressure liquid stream; means forincreasing the velocity of the high-pressure liquid stream and producinga high-velocity supersonic two-phase liquid-vapor stream; 7

means for introducing a low-pressure vapor stream;

means for increasing the velocity of the low-pressure vapor stream;

means for combining said high-velocity, supersonic two-phaseliquid-vapor stream and said low-pressure vapor stream, thereby to forma combined stream which is a two-phase stream and whose density isgreater than the density of the low-pressure vapor stream and less thanthe density of the supersonic two-phase liquid-vapor stream; and

means for decreasing the velocity of said combined stream to a velocityat which the temperature and pressure of the combined stream is greaterthan the temperature and pressure which the low-pressure vapor streamhad before its velocity was increased.

13. An apparatus as set forth in claim 12 wherein the means to increasethe velocity of the high-pressure liquid stream is aconvergent-divergent nozzle.

14. 'Refrigeration system which comprises, in combination:

an input for a liquid refrigerant stream of relatively high pressure;

an ejector comprising an elongated tube having a contoured internalfluid flow path including a mixing chamber with an inlet opening;

means for increasing the velocity of the relatively high pressure liquidrefrigerant stream and producing a supersonic velocity two-phaseliquid-vapor stream, said means comprising a first nozzle discharginginto the inlet opening of said ejector and having a flow axis alignedwith the longitudinal axis of the flow of said ejector;

means .to introduce the liquid refrigerant stream from the input to thefirst nozzle;

-a second nozzle located'concentrically with the first nozzle forintroducing a high velocity vapor refrigerant stream into the inletopening of the mixing chamber and placing stream into intimate contactwiththe two-phase stream formed by the first nozzle, thereby to combinethe streams;

means for decreasing the velocity of the combined streams in the saidchamber to a velocity at which the temperature and pressure of thecombined streams is greater than the temperature and pressure of thevapor refrigerant stream prior to passage through said second nozzle,the last-mentioned means comprising a divergent chamber .of said ejectortube leading from said mixing chamber;

liquid-vapor separator means connected to receive the output from thedivergent chamber and to separate the same into liquid and vaporportions;

vapor compressor means connected to receive the separated vapor portionand to compress the same to a high pressure and temperature;

a heat exchanger to form a condensed refrigerant stream;

means to introduce the compressed vapor from the vapor compressor intothe heat exchanger;

means to withdraw the condensed refrigerant stream from the heatexchanger and to introduce the same to the said input as the said liquidrefrigerant stream of relatively high pressure;

an evaporator to form a vapor refrigerant stream;

means for receiving the said separated liquid portion of theliquid-vapor separator means to expand the same to a lower pressure andtemperature;

10 means to introduce the lower pressure and tempera ture stream intothe evaporator; and means to introduce the vapor refrigerant stream fromthe evaporator into the second nozzle. 15. The refrigeration system ofclaim 14 wherein pressure-increasing means is interposed in the pathbetween the heatexchanger and the said input.

16. The'refirigeration system of claim 15 and in which furtherenergy-supply means is interposed in the said path to increase theenergy of the liquid refrigerant at the said input.

17. An apparatus for compressing a refrigereant vapor which apparatuscomprises, in combination:

a pump to increase the pressure of a liquid refrigerant stream to arelatively high pressure;

an ejector comprising an elongated tube having a contoured internalfluid flow path including a mixing chamber with an inlet opening;

means for increasing the velocity of the relatively high pressure liquidrefrigerant stream and producing a supersonic velocity two-phaseliquidwapor stream, said means comprising a first nozzle discharginginto the inlet opening of said ejector and having a flow axis alignedwith the longitudinal axis of the flow path of said ejector;

means to introduce the liquid refrigerant stream from the pump to thefirst nozzle;

a second nozzle located concentrically with the first nozzle forintroducing a high velocity vapor refrigerant stream into the inletopening of the mixing chamber and placing this stream into intimatecontact with the two-phase stream formed by the first nozzle, thereby tocombine the streams; and

means for decreasing the velocity of the combined streams in the saidchamber to a velocity at which the temperature of the combined streamsis greater than the temperature of the vapor refrigerant stream prior topassage through the second nozzle, the lastrnentioned means comprising adivergent chamber of said ejector tube leading from said mixing chamber.

18. The apparatus of claim 17, wherein the first nozzle is characterizedbya contoured convergent-divergent internal flow path in which theconvergence is sufficiently sharp and the minimum cross-section areasufficiently small to produce said supersonic stream.

19. The apparatus of claim 17, wherein the ejector tube has an internalsection of substantially constant crosssection between the mixingchamber and the divergent chamber.

20. A refrigerant system which comprises in combination:

a pump to increase the pressure of a liquid refrigerant stream to arelatively high pressure; I

an ejector comprising an elongated tube having a contoured internalfluid flow path including a mixing chamber with an inlet opening;

mean-s for increasing the velocity of the relatively high pressureliquid refrigerant stream and producing a supersonic velocity two-phaseliquid-vapor stream, said means comprising a first nozzle dis-charginginto the inlet opening of said ejector and having a flow axis alignedwith the longitudinal axis of the flow path of said ejector;

means to introduce the liquid refrigerant stream from the pump to thefirst nozzle;

a second nozzle located concentrically with the first nozzle forintroducing a high velocity vapor refrigerant stream into the inletopening of the mixing chamber and placing this stream into intimatecontact with the two-phase stream formed by the first nozzle, thereby tocombine the streams;

means for decreasing the velocity of the combined streams in the saidchamber to a velocity at which the temperature of the combined streamsis greater than the temperature of the vapor refrigerant stream prior topassage through said second nozzle, the lastmentioned means comprising adivergent chamberof said ejector tube leading from said mixing chamber;1 a heat exchanger to form a condensed refrigerant stream; v. means tointroduce the refrigerant stream from the divergent chamber into theheat exchanger; 71 means to withdraw a first portion of the condensedrefrigerant stream from the heat exchanger and to introduce that portionto the pump;

i an evaporator to form a vaporrefrigerant stream;

means to withdraw a second portion of the condensed refrigerant streamfrom the heat exchanger and to expand that portion to a'lowerpressureand'temperature; v 7

means to introduce the lower pressure and temperature stream into theevaporator; and If means to introduce the vapor refrigerant stream'fromthe evaporator into the second nozzle. I

21. The refrigeration system of claim 20, wherein the means to introducethe vapor refrigerant stream from the evaporator to the second nozzleincludes a vapor compressor. v

22. The refrigeration system of claim 20, wherein the first nozzle ischaracterized by a contoured convergentdivergent internal fluid flowpath in which the'vconvergence is sumciently-sharp and the minimumcross-section area sufficiently small to produce said supersonic stream.

23. A process for compressing a vapor stream which process comprises: 7,s

- increasing the pressure of a liquid refrigerant. stream to arelatively high pressure; increasing the velocity of a vapor refrigerantstream; increasing the velocity of the pressurized liquid-refrigerantstream and forming a supersonic velocity twophasevapor-liquid.refrigerant stream therefrom; mixing the two-phasevapor-liquid refrigerantstream with the increased velocity vaporrefrigerant stream; alld Y v decreasing the velocity of the mixedstreamstoavelocity at which the temperature .of thefnixed streams is greaterthan the temperature of the vapor refrigerant stream before itsincrease-in velocity. 24. An improved refrigeration process whichcomprises:

increasing the pressure of a liquid refrigerants-stream to a relativelyhigh pressure; 7

increasing the velocity of a vapor refrigerant stream;

increasing the velocity of the pressurized liquid refrig erant streamand forming a supersonievelocitytwophase vapor-liquid refrigerant streamtherefrom; mixing the two-phase vapor-liquid refrigerant stream with theincreased velocity refrigerant stream;

decreasing the velocity of the mixed streams to a velocity at which thetemperature of the mixed streams is greater than the temperature .of thevapor refrigerant stream before its increase in velocity; condensing themixed refrigerant streams";

recycling a first portion of the condensed streams as a liquidrefrigerant stream; expanding a second portion of the condensed streamsto a lower temperature and pressure; and placing the expanded secondportion in a heat absorbing relationship with a heat source to provide.a first vapor refrigerant stream. 7

25. The process of claim 24, which includes compressing the vaporrefrigerant stream prior to its increase in velocity.

26. The process of claim 24, wherein the vapor refrigerant stream isincreased in velocity to form a twophase vapor-liquid stream and bothtwo-phase streams have substantially the same temperature and pressureimmediately prior to mixing.

j "27. 'An apparatus for compressing a refrigerant-vapor which apparatuscomprises; in combination; I

. means for producing a liquid refrigerant stream of a relatively highpressure; f an ejector comprising an elongated tube having a contouredinternal fluid flow path including a mixing chamber with an inletopening; t means for increasing the velocity of the relatively highpressure liquid refrigerant stream and producing a supersonic velocitytwo-phase liquid-vapor stream, said means comprising a first nozzledischarging into the inlet opening of said ejector and having a flowaxis aligned with the longitudinal axis of the flow path of saidejector; r means to introduce the liquid refrigerant stream to the.fi'rst nozzle; I fa second nozzle located concentrically with the firstnozzle for introducing a high velocity vapor refrigrerant stream intothe inlet opening of the mixing chamber and placing this stream intointimate contact with the two-phase stream formed by the first nozzle,thereby to combine the streams; and means for decreasing the velocity ofthe. combined streams in the said chamber to a velocity at which thetemperature and pressure of the combined streams is'greater than thetemperature and pressure of the vapor refrigerant stream prior topassage through the second nozzle, the last-mentioned means com-.prising a divergent chamber of saidejector tube leading from saidmixing chamber. 4 28. The apparatus of claim 27, wherein the firstnozzle is characterizedby a contoured convergent-divergent internal flowpathin which the convergence is suificiently sharp and the minimumcross-section area sufficiently small to produce said supersonicstre-am.29. The apparatus of claim 27, wherein the ejector tube hasv an internalsection of substantially constant cross-section between thernixingchamber sand the divergent chamber. I

30. The apparatus of claim 27, wherein there isfurther i provided; n

a heat exchanger to form a condensed refrigerant stream; t p means tointroduce the refrigerant stream from the divergent chamberinto the heatexchanger;

means to withdraw a first portion ofthe condensed refrigerant streamfrom the heat exchanger. and to introduce that portion to the said firstnozzle;

an evaporator to form a vapor refrigerant stream;

means to withdraw a second portion of the condensed refrigerant streamfrom the heat exchanger and to expand that portion to a lowerpressureand temperature; t r means tofint-roduce thelower pressure andtemperature stream into the evaporator; and v a means to; introduce thevapor refrigerant stream from .the evaporator. into the said secondnozzle.

31. The refrigeration system of claim 30,- wherein the means tointroduce the vapor refrigerant streamfrom theevapora-tor to the secondnozzle includes a vapor compressor.- H 4 Y 32. A process for compressinga vapor stream which process comprises: 1 a r producing a liquidrefrigerant stream of a relatively highpressure-',--"

increasing thevelocity of a vapor refrigerant stream;

- increasing the velocity of the pressurized-liquid refrigcram-streamand forming a supersonic velocity twophase vapor-liquid refrigerantstream therefrom;

mixing the two-phase vapor-liquid refrigerant stream with theincreased-velocity vapor refrigerant stream;

" and-0' decreasing the velocity of the-mixed streams to a velocity atwhich the temperature of the mixed streams is greater than thetemperature of the vapor refrigerant stream before its increase invelocity.

33. A process as claimed in claim 32 and in which the following furthersteps are performed:

condensing the mixed refrigerant streams;

recycling a first portion of the condensed streams as a liquidrefrigerant stream;

expanding a second portion of the condensed streams to a lowertemperature and pressure; and

placing the expanded second portion in a heat absorbing relationshipwith a heat sourceito provide a first vapor refrigerant stream.

References Cited by the Examiner UNITED STATES PATENTS Seligmann 62500Kallam 62-169 X Randel 62-500 X Randel 62-500 Linbolm 62 121 X Neumannet a1. 62S00 LLOYD L. KING, Primary Examiner.

32. A PROCESS FOR COMPRESSING A VAPOR STREAM WHICH PROCESS COMPRISES:PRODUCING A LIQUID REFRIGERANT STREAM OF A RELATIVELY HIGH PRESSURE;INCREASING THE VELOCITY OF A VAPOR REFRIGERANT STREAM; INCREASING THEVELOCITY OF THE PRESSURIZED LIQUID REFRIGERANT STREAM AND FORMING ASUPERSONIC VELOCITY TWOPHASE VAPOR-LIQUID REFRIGERANT STREAM THEREFROM;MIXING THE TWO-PHASE VAPOR-LIQUID REFRIGERANT STREAM WITH THE INCREASEDVELOCITY VAPOR REFRIGERANT STREAM; AND DECREASING THE VELOCITY OF THEMIXED STREAMS TO A VELOCITY AT WHICH THE TEMPERATURE OF THE MIXEDSTREAMS IS GREATER THAN THE TEMPERATURE OF THE VAPOR REFRIGERANT STREAMBEFORE ITS INCREASE IN VELOCITY.